Finally got to uploading pictures of my satellite work. My main job in ESTCube-1 has been designing electronics. This is the first board I did for the satellite. It is Electrical Power System microcontroller board that measures and controls whole satellite power.

The form factor is very typical for cubesats. 94mm x 94mm PCB with 3mm grounded holes in all corners. The big sea of pads on the top is main stack connector. Also very common in such satellites: 4x30 pins with 2mm pitch. Usually the cubesats are divided to subsystems. Each subsystem has one or more PCBs in main PCB stack and they all communicate through main connector. This makes possible for hardware teams to work separately and provides maximum amount of standardization. And standardization leads to commercialization. And that - to cheaper and better quality products.

Power tracks in middle layer

Now the oddities of the board. As you can see there is a big hole in the middle, this is for accommodating batteries. It made routing the board much more fun. It is a 4 layer board with a ground plane on all the layers. Top and bottom layers are mostly for signals (less vias, better to debug). One of the inner layer has the power tracks on. The connector on the bottom side connects to other Power System board that has all the main regulators and switches on.

Bottom side of the Power System MCU board

Ribbon cable is for JTAG programming. It was meant to have a connector but connector was too bulky to fit in the stack, so, until we make new board with Micro-MaTch connectors it stays that way. The other wires are for temporary power input and regulator enable.

Unfortunately no high-resolution pictures, part numbers or schematics. The university doesn't like to open source project that they are planning to sell so I was allowed only to show of pictures.